In the acetone cyanohydrin-methyl methacrylate (ACH-MMA) process, acetone cyanohydrin is added to an excess of sulfuric acid (1.4-1.8 mol/mol ACH), which acts as both reactant and solvent. The reaction between ACH and sulfuric acid produces α-sulfatoisobutyramide, which then undergoes an elimination reaction under the heated process conditions to give methacrylamide sulfate.

In the next stage, sulfuric acid serves as catalyst in a combined hydrolysis/esterification of the methacrylamide sulfate to a mixture of MMA and methylacrylic acid (MAA).

In one scheme, the methacrylamide sulfate is reacted with aqueous methanol in a continuous reactor or a series of reactors at temperatures of from 100 to 150° C.
In the industrial process for the manufacture of methyl methacrylate (MMA), an aqueous sulfuric acid waste stream (spent acid) is produced. This spent acid stream is concentrated with sulfuric acid (H2SO4), ammonium bisulfate (NH4.HSO4) and residual organic components. The organic components generally comprise a high proportion of residues and tars and smaller quantities of lighter organic compounds.
Due to the highly contaminated nature of MMA spent acid, the current industrial treatment method available for acid recovery and concentration is that involving regeneration. In this process, the spent acid is decomposed in a brick-lined furnace at about 1000° C. At this temperature, the organic components in the spent acid are oxidized to carbon dioxide and water, the ammonium salts are converted to nitrogen and sulfur dioxide; and the sulfuric acid is reduced to sulfur dioxide. The sulfur dioxide gas stream produced in the regeneration process passes through heat recovery and gas cleaning processes before being converted to sulfuric acid in a conventional contact acid plant.
Polymerization of MMA, MAA, methacrylamide or other vinyl monomers is undesirable and very common in the manufacturing processes for preparing an acrylate, methacrylic acid, or a methacrylate monomer. In the MMA manufacturing process, polymers formed from MMA, MAA, and other vinyl monomers flow out of the process with the spent acid. Many of the polymers formed have a lower density than the spent acid, so they float in the aqueous acid and when they agglomerate, precipitate out of the spent acid, or deposit on the equipment, they can cause process operating problems.
Polymer formation, agglomeration, and fouling are generally a concern for the processes for handling an acrylate, methacrylic acid, or a methacrylate monomer. A sulfuric acid-containing waste stream often carries the polymer. Reducing or preventing the operation problems and disposing of the waste stream are challenging and costly goals.
A method for removing these polymer agglomerates or deposits once they form and for preventing agglomeration or deposition of the polymers before they are formed is a need for the process.